High-lift device, wing, and noise reduction structure for high-lift device

ABSTRACT

A high-lift device suppresses the occurrence of aerodynamic noise while minimizing an increase in airframe weight. The device includes a slat main body disposed to be able to extend from and retract into a main wing, and a concave part formed on the slat main body at a location facing the main wing and able to accommodate at least a part of a leading edge of the main wing. The device also includes an airflow control part disposed at an area in the concave part facing an upper surface of the main wing, that is accommodated between the main wing and the concave part when the slat main body is retracted into the main wing, and that suppresses turbulence colliding against the area in the concave part facing the upper surface of the main wing when the slat main body is extended from the main wing.

This application is a divisional of Ser. No. 12/526,800, filed on Aug.12, 2009 which is a National Stage Application of InternationalApplication Serial No. PCT/JP2008/059215, filed May 20, 2008.

TECHNICAL FIELD

The present invention relates to high-lift devices, wings, and noisereduction structures for high-lift devices that are suitable, forexample, for suppressing the occurrence of aerodynamic noise.

BACKGROUND ART

Noise generated by aircraft at the time of takeoff and landing is alarge problem for the environment around airports. This noise includesengine noise and aerodynamic noise generated from high-lift devices(such as, slats and flaps), the undercarriage, etc.

Since the high-lift devices, which are one of the sources of theabove-mentioned noise, are used to obtain aerodynamic characteristicsrequired at the time of takeoff and landing of the aircraft, they aredesigned with an emphasis on their aerodynamic characteristics, whereasnoise reduction is not taken into consideration.

However, since the noise is a large problem as described above, effortshave been made to reduce the noise of the high-lift devices as well. Forexample, technologies for achieving a reduction in noise generated atslats serving as the high-lift devices have been proposed (for example,see U.S. Pat. No. 6,394,396).

U.S. Pat. No. 6,394,396 describes a technology in which a balloon thatcan be inflated and deflated is disposed on a concave part of a slatfacing a main wing.

With this technology, when the slat is extended (separated) from themain wing, the balloon is inflated to fill the concave part, thussuppressing the occurrence of aerodynamic noise due to turbulence causedby the concave part.

The concave part is provided to ensure space for avoiding interferencewith the leading edge of the main wing when the slat is retracted into(is brought into contact with) the main wing.

SUMMARY OF THE INVENTION

However, with the technology described in U.S. Pat. No. 6,394,396, inaddition to a mechanism that makes the slat extend from and retract intothe main wing, a mechanism that inflates and deflates the balloon needsto be disposed inside the main wing or the like. There is less extraspace inside the main wing or the like, leading to a structural(spatial) problem in disposing the mechanism.

In particular, in order to inflate the balloon, high-pressure air needsto be supplied to the balloon. In order to supply the high-pressure air,it is necessary to provide a special compressor or to provide pipes,etc. for guiding the high-pressure air from the engines. There is astructural (spatial) problem in disposing such a mechanism.

Further, there is a problem in that the airframe weight of the aircraftis increased when such a mechanism is added.

The present invention has been made to solve the above-mentionedproblems, and an object thereof is to provide high-lift devices, wings,and noise reduction structures for high-lift devices capable ofsuppressing the occurrence of aerodynamic noise while restricting anincrease in airframe weight.

In order to achieve the above-described object, the present inventionprovides the following solutions.

A first aspect of the present invention relates to a high-lift deviceincluding a slat main body that is disposed so as to be able to extendfrom and retract into a main wing; a concave part that is formed on theslat main body at a location that faces the main wing, so as to be ableto accommodate at least a part of a leading edge of the main wing; andan airflow control part that is disposed at an area in the concave partfacing an upper surface of the main wing, that is accommodated betweenthe main wing and the concave part when the slat main body is retractedinto the main wing, and that suppresses the turbulence colliding againstthe area in the concave part facing the upper surface of the main wingwhen the slat main body is extended from the main wing.

According to the first aspect of the present invention, when the slatmain body is retracted into the main wing, the concave part accommodatesthe leading edge of the main wing. At this time, the airflow controlpart is accommodated between the main wing and the concave part. Thus,the leading edge of the main wing can be formed in a shape that does notimpair the aerodynamic characteristics, without considering interferencewith the airflow control part.

Not impairing the aerodynamic characteristics means that, for example,the aerodynamic lift characteristics are not impaired in the state wherethe slat main body is extended from or retracted into the main wing.

Specifically, in the state where the slat main body is retracted intothe main wing, the airflow control part is accommodated between the mainwing and the concave part. Thus, turbulence around the main wing and theslat main body is not caused, and the aerodynamic lift characteristics,etc. are not impaired. On the other hand, in the state where the slatmain body is extended from the main wing, turbulence between the slatmain body and the main wing is not caused by the airflow control part,and the aerodynamic lift characteristics, etc. are not impaired.

When the slat main body is extended from the main wing, part of the airflows along the lower surface of the slat main body and is separatedfrom the lower surface. The separated air (shear layer) flows betweenthe slat main body and the main wing, collides against the airflowcontrol part, and flows along the airflow control part and the surfaceof the concave part.

The airflow control part can suppress the turbulence colliding againstthe area in the concave part facing the upper surface of the main wing,in other words, against the airflow control part. Therefore, comparedwith a case where the airflow control part is not provided, it ispossible to suppress the occurrence of aerodynamic noise caused byturbulence.

Further, compared with the technology described in U.S. Pat. No.6,394,396, a smaller number of components is required, restricting anincrease in weight.

The airflow control part can suppress the turbulence colliding againstthe area in the concave part facing the upper surface of the main wing,in other words, against the airflow control part. Therefore, comparedwith a case where the airflow control part is not provided, it ispossible to suppress the occurrence of aerodynamic noise caused byturbulence.

Further, compared with the technology described in Patent Document 1, asmaller number of components is required, restricting an increase inweight.

In the first aspect of the invention, it is desirable to have astructure in which the airflow control part includes an inclined platethat is provided at the area in the concave part facing the uppersurface of the main wing and whose angle with respect to the centralaxis of the slat main body can be deflected.

Accordingly, the angle of the inclined plate can be deflected at anangle for avoiding interference with the upper surface of the main wing.Thus, the leading edge of the wing can be formed in a shape that doesnot impair the aerodynamic characteristics, without consideringinterference with the inclined plate.

When the slat main body is extended from the main wing, an air (shearlayer) separated from the lower surface of the slat main body flowsbetween the slat main body and the main wing, collides against theinclined plate, and flows along the inclined plate and the surface ofthe concave part.

Since the angle of the inclined plate with respect to theabove-mentioned central axis can be deflected, the collision angle ofthe shear layer and the inclined plate can be deflected. Therefore,compared with a case where the collision angle cannot be deflected, itis possible to suppress the occurrence of aerodynamic noise by selectinga collision angle at which less aerodynamic noise occurs.

In the above-described structure, it is desirable that one end of theinclined plate that is close to the main wing is pivotably supported onthe slat main body; and the other end of the inclined plate ispositioned at a location where interference with the leading edge of themain wing does not occur and aerodynamic characteristics are notimpaired, in a state where the slat main body is retracted into the mainwing, and moves downward with respect to the central axis when the slatmain body is extended from the main wing.

Accordingly, when the slat main body is retracted into the main wing,the other end of the inclined plate pivots toward a location whereinterference with the leading edge of the main wing does not occur andthe aerodynamic characteristics are not impaired, in other words, itpivots upward about the one end (that is, in a direction in which itmoves away from the central axis). Therefore, it is possible to avoidinterference by widening a gap between the inclined plate and the uppersurface of the main wing.

When the slat main body is extended from the main wing, the other end ofthe inclined plate pivots about the one end downward with respect to thecentral axis (that is, in a direction in which it approaches the centralaxis). Therefore, the collision angle of the shear layer and theinclined plate can be reduced.

In the above-described structure, it is desirable to further include aseal part that extends in a direction in which the slat main bodyextends and that is brought into contact with the area in the concavepart facing the upper surface of the main wing and is deformed when theslat main body is retracted into the main wing, in which: one end of theinclined plate that is close to the main wing is pivotably supported onthe slat main body; and the other end of the inclined plate is supportedon the seal part.

Accordingly, when the slat main body is retracted into the main wing,the seal part is brought into contact with the upper surface of the mainwing. Therefore, a gap between the slat main body and the main wing issealed, thus preventing water, dust, etc. from entering the concavepart.

Further, since the seal part is brought into contact with the uppersurface of the main wing and is deformed, the other end of the inclinedplate is deformed toward a location where interference with the leadingedge of the main wing does not occur and the aerodynamic characteristicsare not impaired. In other words, the other end of the inclined plate isdeformed upward about the one end (that is, in a direction in which itmoves away from the central axis). Therefore, the airflow control partis accommodated in the gap between the slat main body and the uppersurface of the main wing without interference.

On the other hand, when the slat main body is extended from the mainwing, the shape of the seal part that was in contact with and pressed bythe upper surface of the main wing is restored. Accordingly, the shapeof the inclined plate that was deformed upward with respect to thecentral axis about the one end is also restored at the other end of theinclined plate. Therefore, the collision angle of the above-mentionedshear layer and the inclined plate can be reduced.

In the above-described structure, it is desirable that the inclinedplate is made of a material that has elasticity.

If the seal part, etc. are made of an elastic material, for example, theinclined plate is also made of the elastic material, thereby allowingthe inclined plate and the seal part, etc. to be integrally formed.

In the first aspect of the invention, it is desirable that the airflowcontrol part includes a shock absorbing part that absorbs part of energymade by air flowing toward the area facing the upper surface of the mainwing.

Accordingly, when the slat main body is extended from the main wing, anair (shear layer) separated from the lower surface of the slat main bodyflows between the slat main body and the main wing, collides against theshock absorbing part, and flows along the shock absorbing part and thesurface of the concave part.

When the separated air collides against the shock absorbing part, theshock absorbing part absorbs part of the energy of the airflow.Therefore, it is possible to reduce the aerodynamic noise generated bythe airflow after it collides against the shock absorbing part.

In the first aspect of the invention, it is desirable to further includea lower-surface plate that is a plate-like member extending toward themain wing from an edge line at which the lower surface of the slat mainbody and the concave part meet, and whose angle with respect to thecentral axis can be deflected.

Accordingly, when the slat main body is retracted into the main wing,the concave part accommodates the leading edge of the main wing. At thistime, since the angle of the lower-surface plate with respect to thecentral axis can be deflected, the angle of the lower-surface plate withrespect to the central axis is deflected at an angle for smoothlyconnecting the lower surface of the slat main body to the lower surfaceof the main wing. Thus, deterioration in the aerodynamic characteristicsof the wing, having the slat main body and the main wing, can beprevented.

When the slat main body is extended from the main wing, part of the airflows along the lower surface of the slat main body and thelower-surface plate and is separated from the lower-surface plate. Sincethe angle of the lower-surface plate with respect to the central axiscan be deflected, the direction of the separated air can be deflected.Thus, compared with a case where the airflow is separated from thelower-surface plate positioned in the same state as when the slat mainbody is retracted into the main wing, the direction of the separated aircan be deflected to weaken the shear layer, thereby suppressing theoccurrence of aerodynamic noise.

On the other hand, the separated air flows between the slat main bodyand the main wing, collides against the inclined plate, and flows alongthe inclined plate and the surface of the concave part.

Since the angle of the lower-surface plate with respect to the centralaxis can be deflected, it is possible to deflect the direction of theseparated air to deflect the collision angle of the separated air withrespect to the inclined plate. Therefore, compared with a case where thedirection of the separated air cannot be deflected, it is possible tosuppress the occurrence of aerodynamic noise by selecting a collisionangle at which less aerodynamic noise occurs.

In the first aspect of the invention, it is desirable that alower-surface plate that is a plate-like member extending toward themain wing from an edge line at which the lower surface of the slat mainbody and the concave part meet, and whose angle with respect to thecentral axis can be deflected is further included; the lower-surfaceplate is pivotably supported at the edge line on the slat main body; andthe other end of the lower-surface plate is positioned at a locationwhere interference with the leading edge of the main wing does not occurand aerodynamic characteristics are not impaired, in a state where theslat main body is retracted into the main wing, and moves upward ordownward with respect to the central axis when the slat main body isextended from the main wing.

Accordingly, when the slat main body is retracted into the main wing,the end of the lower-surface plate that is close to the main wing pivotstoward a location where interference with the leading edge of the mainwing does not occur and the aerodynamic characteristics are notimpaired, in other words, it pivots downward (that is, in a direction inwhich it moves away from the central axis). Therefore, interferencebetween the lower-surface plate and the leading edge of the main wing isavoided. Further, the lower-surface plate can smoothly connect the lowersurface of the slat main body to the lower surface of the main wing.

When the slat main body is extended from the main wing, the end of thelower-surface plate that is close to the main wing pivots upward withrespect to the central axis (that is, in a direction in which itapproaches the central axis). Therefore, the direction of the separatedair is deflected to reduce the collision angle of the separated air withrespect to the inclined plate, thereby allowing suppression of theoccurrence of aerodynamic noise.

On the other hand, even when the end of the lower-surface plate that isclose to the main wing pivots downward with respect to the central axis(in other words, in a direction in which it moves away from the centralaxis), if a porous plate or serrations are used for the lower-surfaceplate, for example, the shear layer of the separated air is weakened toallow a reduction in aerodynamic noise.

In the first aspect of the invention, it is desirable that alower-surface plate that is a plate-like member extending toward themain wing from an edge line at which the lower surface of the slat mainbody and the concave part meet, and whose angle with respect to thecentral axis can be deflected is further included; and the lower-surfaceplate is made of one of a member through which an air does not pass, amember through which part of the air passes, a member having serrationsat the end thereof close to the main wing, or a combination thereof.

Accordingly, when a member through which part of the air passes is usedfor the lower-surface plate, the shear layer of the separated air isweakened to allow a reduction in aerodynamic noise.

When serrations are provided at the end of the lower-surface plate thatis close to the main wing, the shear layer of the separated air isweakened to allow a reduction in aerodynamic noise irrespective ofwhether the lower-surface plate is made of a member through which partof the air passes or a member through which the air does not pass.

Examples of the member through which part of the air passes include aporous plate and mesh-like plate. The serrations means the trailing edgeformed in a saw-like shape along the longitudinal direction of thelower-surface plate.

A second aspect of the present invention relates to a wing including amain wing; and a high-lift device according to the first aspect of thepresent invention that is disposed so as to be able to extend from andretract into a leading edge of the main wing.

According to the second aspect of the present invention, the high-liftdevice of the present invention is provided, thereby suppressing theoccurrence of aerodynamic noise while restricting an increase in weight.

A third aspect of the present invention relates to a noise reductionstructure for a high-lift device including an airflow control part thatis accommodated between a main wing and a concave part formed on a slatmain body at a location facing the main wing, so as to be able toaccommodate at least a part of a leading edge of the main wing when theslat main body, which is disposed so as to be able to extend from andretract into the main wing, is retracted into the main wing; and thatsuppresses the turbulence colliding against an upper surface of the mainwing when the slat main body is extended from the main wing.

According to the third aspect of the present invention, when the slatmain body is retracted into the main wing, the airflow control part isaccommodated between the main wing and the concave part. Therefore, theleading edge of the main wing can be formed in a shape that does notimpair the aerodynamic characteristics, without considering interferencewith the airflow control part.

When the slat main body is extended from the main wing, an air (shearlayer) separated from the lower surface of the slat main body flowsbetween the slat main body and the main wing, collides against theairflow control part, and flows along the airflow control part and thesurface of the concave part.

Since the airflow control part can suppress the turbulence collidingagainst the airflow control part, it is possible to suppress theoccurrence of aerodynamic noise caused by turbulence compared with acase where the airflow control part is not provided.

With the high-lift device according to the first aspect of the presentinvention, the wing according to the second aspect thereof, and thenoise reduction structure for a high-lift device, according to the thirdaspect thereof, it is possible to suppress the turbulence collidingagainst the airflow control part. Therefore, compared with a case wherethe airflow control part is not provided, it is possible to suppress theoccurrence of aerodynamic noise caused by turbulence.

Since a smaller number of components is required, there is an effect inthat an increase in the airframe weight can be prevented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for explaining an outline of a wing according to afirst embodiment of the present invention and is a partial enlarged viewfor explaining a state where a slat is retracted.

FIG. 2 is a partial enlarged view for explaining a state where the slatis extended in the wing shown in FIG. 1.

FIG. 3 is a schematic view for explaining the structure of the slatshown in FIG. 1.

FIG. 4 is a view for explaining an outline of a measurement system usedto measure aerodynamic noise from the wing shown in FIG. 1 and others.

FIG. 5 is a view for explaining the shape of a conventional slat whoseaerodynamic noise is measured by the measurement system shown in FIG. 4.

FIG. 6 is a view for explaining the shape of a slat that has only alower-surface plate of this embodiment and whose aerodynamic noise ismeasured by the measurement system shown in FIG. 4.

FIG. 7 is a view for explaining the shape of a slat that has only anairflow control part of this embodiment and whose aerodynamic noise ismeasured by the measurement system shown in FIG. 4.

FIG. 8 is a view for explaining the shape of the slat of thisembodiment, whose aerodynamic noise is measured by the measurementsystem shown in FIG. 4.

FIG. 9 is a view for explaining the shape of a slat described in U.S.Pat. No. 6,394,396, whose aerodynamic noise is measured by themeasurement system shown in FIG. 4.

FIG. 10 shows graphs indicating measurement results of aerodynamic noisefrom the slats shown in FIGS. 5 to 9.

FIG. 11 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 5 and the main wing when the slatis extended.

FIG. 12 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 6 and the main wing when the slatis extended.

FIG. 13 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 7 and the main wing when the slatis extended.

FIG. 14 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 8 and the main wing when the slatis extended.

FIG. 15 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 9 and the main wing when the slatis extended.

FIG. 16 is a cross-sectional view for explaining the structure of a slataccording to a second embodiment of the present invention.

FIG. 17 is a cross-sectional view for explaining the structure of anairflow control part shown in FIG. 16.

FIG. 18 is a cross-sectional view for explaining a structure formounting the airflow control part shown in FIG. 17 to the slat.

FIG. 19 is a view for explaining the state of the airflow control partwhen the slat is extended from the main wing.

FIG. 20 is a view for explaining the state of the airflow control partwhen the slat is refracted into the main wing.

FIG. 21 is a cross-sectional view for explaining another embodiment ofthe airflow control part shown in FIG. 17.

FIG. 22 is a cross-sectional view for explaining a structure formounting an airflow control part shown in FIG. 21 to the slat.

FIG. 23 is a cross-sectional view for explaining still anotherembodiment of the airflow control part shown in FIG. 17.

FIG. 24 is a cross-sectional view for explaining the structure of anairflow control part according to a third embodiment of the presentinvention.

FIG. 25 is a schematic partial plan view of a lower-surface plate havingserrations at its trailing edge.

EXPLANATION OF REFERENCE SIGNS

-   1, 101, 201: wing-   2: main wing-   3: slat (high-lift device)-   4: slat main body-   5: cove (concave part)-   6: inclined plate (airflow control part, noise reduction structure)-   7: lower-surface plate-   12: inclined surface-   13: edge line-   106, 206: airflow control part (noise reduction structure)-   113, 113A: inclined plate-   213: shock absorbing part

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

A wing according to a first embodiment of the present invention will bedescribed with reference to FIGS. 1 to 15.

FIG. 1 is a view for explaining an outline of the wing according to thisembodiment and is a partial enlarged view for explaining a state where aslat is retracted. FIG. 2 is a partial enlarged view for explaining astate where the slat is extended in the wing shown in FIG. 1.

As shown in FIGS. 1 and 2, a wing 1 includes a main wing 2 and a slat(high-lift device) 3.

The main wing 2 is a member constituting the wing 1 together with theslat 3. The main wing 2 is formed to have an airfoil section to realizerequired aerodynamic characteristics when the slat 3 is retracted toserve as the wing 1 and when the slat 3 is extended to serve as thepaired main wing 2 and slat 3.

The slat 3 is disposed at the leading edge of the main wing 2. A drivemechanism (not shown) that retracts and extends the slat 3 is providedinside the main wing 2.

Note that the wing 1 may be constituted by only the main wing 2 and theslat 3, as described above, or another high-lift device, such as a flap,may additionally be disposed at the trailing edge of the main wing 2;the structure of the wing 1 is not particularly limited.

When the slat 3 is retracted as shown in FIG. 1, the slat 3 is broughtinto contact with the leading edge (the left end in FIG. 1) of the mainwing 2, and the main wing 2 and the slat 3 integrally form the wing 1.On the other hand, when the slat 3 is extended as shown in FIG. 2, theslat 3 is lowered diagonally forward from the leading edge of the mainwing 2 to produce a gap between the main wing 2 and the slat 3.

Further, the slat 3 pivots about the longitudinal axis of the slat 3(the axis perpendicular to the plane of the paper of FIGS. 1 and 2) whenbeing extended from the retracted state or when being retracted from theextended state. Specifically, when the slat 3 is extended from theretracted state, the slat 3 pivots (counterclockwise in FIG. 2) suchthat the leading edge of the slat 3 moves downward; and, when the slat 3is retracted from the extended state, the slat 3 pivots (clockwise inFIG. 1) such that the leading edge of the slat 3 moves upward.

FIG. 3 is a schematic view for explaining the structure of the slatshown in FIG. 1.

As shown in FIG. 3, the slat 3 includes a slat main body 4, a cove(concave part) 5, an inclined plate (airflow control part, noisereduction structure) 6, and a lower-surface plate 7.

The slat main body 4 is a member constituting the wing 1 together withthe main wing 2 and is formed to have an airfoil section to realizerequired aerodynamic characteristics when the slat 3 is retracted toserve as the wing 1 and when the slat 3 is extended to serve as thepaired slat 3 and main wing 2.

The slat main body 4 has a leading edge 8 serving as an air upstreamend, and an upper surface 9 and a lower surface 10 along which an airflows. The cove 5 is formed on the slat main body 4 at a location thatfaces the main wing 2.

The upper surface 9 smoothly extends from the leading edge 8 andprojects toward the main wing 2 further than the lower surface 10. Thelower surface 10 smoothly extends from the leading edge 8 and has thelower-surface plate 7 disposed at the downstream end thereof.

The cove 5 is a concave part formed on the slat main body 4 at an areathat faces the main wing 2 and accommodates the leading edge of the mainwing 2 when the slat 3 is retracted.

In this embodiment, a description will be given of an example case wherethe cove 5 is formed by a front part of the cove 5 that is a surfaceperpendicular to a central axis CL and a rear part of the cove 5 that isan opposing surface that approaches the upper surface 9 toward the mainwing 2. Note that the cove 5 is not limited to the above-mentionedstructure, and it may have a single curved surface; the structurethereof is not particularly limited.

The inclined plate 6 is a plate-like member against which an airflowseparated at the lower-surface plate 7 collides. The inclined plate 6 ispivotably supported with respect to the rear part of the cove 5 at apivotal end (one end) 11 close to the main wing 2 (at the right side inFIG. 3). In other words, the inclined plate 6 is supported such that theend thereof close to the leading edge 8 (at the left side in FIG. 3) canextend from and retract into the central axis CL. The inclined plate 6has surfaces inclined upward toward the main wing 2.

The inclined plate 6 is biased by an elastic member, such as a spring,in a direction in which the end thereof close to the leading edge 8approaches the central axis CL. As a result, when the slat 3 isextended, the inclined plate 6 pivots by means of the elastic member inthe direction in which the end thereof close to the leading edge 8approaches the central axis CL. On the other hand, when the slat 3 isretracted, the inclined plate 6 is pressed by the upper surface of themain wing 2 to pivot in a direction in which the end thereof close tothe leading edge 8 moves away from the central axis CL.

An inclined surface 12 of the inclined plate 6 that faces the main wing2 is a surface against which the above-mentioned separated air collidesand along which the colliding air flows.

Note that the inclined plate 6 may be configured such that theplate-like member is pivotably disposed as in the above-describedembodiment, or it may be configured such that a wedge-shaped airflowcontrol part is disposed so as to be able to retract and to extend withrespect to the slat main body 4; the structure of the inclined plate 6is not particularly limited.

The lower-surface plate 7 is a plate-like member extending toward themain wing 2 from an edge line 13 at which the lower surface 10 and thecove 5 meet. The lower-surface plate 7 is connected to the edge line 13at a pivotal part 14 and is supported so as to be pivotable about thepivotal part 14. In other words, the lower-surface plate 7 is supportedsuch that an end thereof close to the main wing 2 (at the right side inFIG. 3) can extend from and retract into the central axis CL.

The lower-surface plate 7 may be made of a plate-like member throughwhich an air does not pass or it may be made by using a member, such asa porous plate or a mesh-like plate, through which part of the airpasses; the member used for the lower-surface plate 7 is notparticularly limited.

When the lower-surface plate 7 is made by using a member through whichpart of the air passes, a shear layer of the separated air is weakenedto allow a reduction in aerodynamic noise.

Further, serrations 27, formed in a saw-like shape, may be provided atthe trailing edge (the right edge in FIG. 3) of the lower-surface plate7 along the longitudinal direction (the direction perpendicular to theplane of the paper of FIG. 3) of the lower-surface plate 7 asillustrated in FIG. 25; the provision of serrations is not particularlylimited.

When serrations 27 are provided at the trailing edge of thelower-surface plate 7, the shear layer of the separated air is weakenedto allow a reduction in aerodynamic noise irrespective of whether thelower-surface plate 7 is made of a member through which the air does notpass or a member through which part of the air passes.

Next, the operation of the wing 1, having the above-described structure,will be described.

The slat 3 of the wing 1 is extended from the main wing 2, as shown inFIG. 2, at the time of takeoff and landing, and it is retracted, asshown in FIG. 1, during cruising.

Note that the degree of extension of the slat 3 is different betweentakeoff and landing, and the slat 3 is extended more at landing than attakeoff. In this embodiment, a description will be given mainly of anoperation performed at the time of landing, during which moreaerodynamic noise is generated from the slat 3.

When aircraft provided with the wing 1 is about to land, the slat 3 isextended from the main wing 2, as shown in FIG. 2, in order to realizethe aerodynamic characteristics required at the time of landing.Specifically, the slat 3 is extended to increase an angle of attack atwhich the wing 1 causes stalling, in other words, the slat 3 is extendedso as not to cause stalling until a large angle of attack.

At the same time, the end of the inclined plate 6 that is close to theleading edge 8 pivots downward about the pivotal end 11. On the otherhand, the end of the lower-surface plate 7 that is close to the mainwing 2 pivots upward about the pivotal part 14.

When the aircraft provided with the wing 1 is in a cruising state, theslat 3 is retracted into the main wing 2, as shown in FIG. 1.

At this time, the end of the inclined plate 6 that is close to theleading edge 8 pivots upward about the pivotal end 11, and the inclinedplate 6 moves to a location along the rear part of the cove 5. Thus, itis possible to avoid interference between the inclined plate 6 and theleading edge and upper surface of the main wing 2.

On the other hand, the end of the lower-surface plate 7 that is close tothe main wing 2 pivots about the pivotal part 14 downward from thecentral axis CL and moves to a location where the lower surface 10 ofthe slat main body 4 is smoothly connected to the lower surface of themain wing 2. Thus, it is possible to avoid interference between thelower-surface plate 7 and the main wing 2 and also to preventdeterioration in the aerodynamic characteristics of the wing 1.

Next, measurement results of aerodynamic noise from the wing 1 of thisembodiment will be described. A description will be given of comparisonswith a conventional wing adopting no measures to reduce aerodynamicnoise, the wing described in U.S. Pat. No. 6,394,396, and modificationsof the wing 1 of this embodiment.

First, a measurement system will be described.

FIG. 4 is a view for explaining an outline of the measurement systemused to measure aerodynamic noise from the wing shown in FIG. 1 andothers.

As shown in FIG. 4, a measurement system 15 includes a wind tunnelnozzle 16 that produces an air toward the wing 1 and a microphone 17that measures aerodynamic noise generated from the wing 1.

An outlet of the wind tunnel nozzle 16 is disposed at a location a wingchord length C away from the leading edge 8 of the wing 1 (or of theslat main body 4).

The microphone 17 is disposed at the lower surface side of the wing 1 ata distance sufficient for far-field acoustic measurement. In otherwords, it is disposed at a location 10C away from the lower surface 10of the wing 1.

FIG. 5 is a view for explaining the shape of a conventional slat whoseaerodynamic noise is measured by the measurement system shown in FIG. 4.

As shown in FIG. 5, a slat 3A of the conventional wing, whoseaerodynamic noise is measured as a target for comparison with the wing 1of this embodiment, has a lower-surface plate 7A extending along thelower surface 10 of the slat main body 4 and has space in a cove 5A toavoid interference with the main wing. The attachment angle of thelower-surface plate 7A is fixed.

FIG. 6 is a view for explaining the shape of a slat that has only thelower-surface plate of this embodiment and whose aerodynamic noise ismeasured by the measurement system shown in FIG. 4.

As shown in FIG. 6, in a slat 3B that has only the lower-surface plate 7of this embodiment, whose aerodynamic noise is measured as a target forcomparison with the wing 1 of this embodiment, the lower-surface plate 7is fixed in a state where it has pivoted toward the central axis CL.

FIG. 7 is a view for explaining the shape of a slat that has only theairflow control part of this embodiment and whose aerodynamic noise ismeasured by the measurement system shown in FIG. 4.

As shown in FIG. 7, a slat 3C that has only the inclined plate 6 of thisembodiment, whose aerodynamic noise is measured as a target forcomparison with the wing 1 of this embodiment, includes thelower-surface plate 7A extending along the lower surface 10 of the slatmain body 4. In the cove 5, the inclined plate 6 of this embodiment isfixed in a state where the end thereof close to the slat main body 4 haspivoted toward the central axis CL.

FIG. 8 is a view for explaining the shape of the slat of thisembodiment, whose aerodynamic noise is measured by the measurementsystem shown in FIG. 4.

As shown in FIG. 8, in the slat 3 of this embodiment, whose aerodynamicnoise is measured as a target for comparison with the wing 1 of thisembodiment, the lower-surface plate 7 is fixed in a state where it haspivoted toward the central axis CL, and the inclined plate 6 is fixed ina state where it has pivoted toward the central axis CL.

FIG. 9 is a view for explaining the shape of the slat described in U.S.Pat. No. 6,394,396, whose aerodynamic noise is measured by themeasurement system shown in FIG. 4.

As shown in FIG. 9, a slat 3D described in U.S. Pat. No. 6,394,396,whose aerodynamic noise is measured as a target for comparison with thewing 1 of this embodiment, includes a filling member 19 that fills thecove 5 and that has a curved surface 18 for guiding an air flowing alongthe lower surface 10 of the slat main body 4.

FIG. 10 shows graphs indicating measurement results of aerodynamic noisefrom the slats shown in FIGS. 5 to 9.

In FIG. 10, a thick line shows a graph indicating the sound pressurelevel (SPL (dB)) of aerodynamic noise from the slat 3A (see FIG. 5),outline diamond shapes (⋄) show a graph indicating the sound pressurelevel of aerodynamic noise from the slat 3B (see FIG. 6), solidtriangles (▴) show a graph indicating the sound pressure level ofaerodynamic noise from the slat 3C (see FIG. 7), outline circles (◯)show a graph indicating the sound pressure level of aerodynamic noisefrom the slat 3 (see FIG. 8) of this embodiment, and the crosses (X)show a graph indicating the sound pressure level of aerodynamic noisefrom the slat 3D (see FIG. 9).

As shown in FIG. 10, the sound pressure level of the aerodynamic noisefrom the slat 3D is the lowest, followed by the sound pressure level ofaerodynamic noise from the slat 3. The sound pressure level is thenincreased in the order of the slat 3C and the slat 3B, the soundpressure level of aerodynamic noise from the slat 3A being the highest.

Next, a description will be given of a flow field produced around eachslat and the main wing when the slat is extended.

FIG. 11 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 5 and the main wing when the slatis extended.

When the slat 3A is extended from the main wing 2, an air flows alongthe leading edge 8 of the slat main body 4, part thereof flows from theleading edge 8 along the upper surface 9, and the rest thereof flowsfrom the leading edge 8 along the lower surface 10, as shown in FIG. 11.

The air flowing along the lower surface 10 flows from the lower surface10 along the lower-surface plate 7A and is separated at the end of thelower-surface plate 7A. The separated air flows in the direction inwhich the lower-surface plate 7A extends, and then flows between thecove 5 of the slat main body 4 and the main wing 2 to collide againstthe rear part of the cove 5. The colliding air flows along the rear partof the cove 5, joins the air flowing along the upper surface 9, andflows along the upper surface of the main wing 2.

This aspect indicates a conventional aspect of the slat.

FIG. 12 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 6 and the main wing when the slatis extended.

When the slat 3B is extended from the main wing 2, as shown in FIG. 12,part of the air flows from the leading edge 8 along the upper surface 9,and the rest thereof flows from the leading edge 8 along the lowersurface 10, in the same way as described above.

The air flowing along the lower surface 10 flows from the lower surface10 along the lower-surface plate 7 and is separated at the end of thelower-surface plate 7. The separated air flows in the direction in whichthe lower-surface plate 7 extends, and then flows between the cove 5A ofthe slat main body 4 and the main wing 2 to collide against the rearpart of the cove 5A. The colliding air flows along the rear part of thecove 5A, joins the air flowing along the upper surface 9, and flowsalong the upper surface of the main wing 2.

Compared with the above-described slat 3A of the conventional aspect,the air separated from the end of the lower-surface plate 7 flows whilebeing deflected toward the cove 5A, thereby weakening the shear layer ofthe separated air. Further, the separated air is deflected, therebyreducing the collision angle of the airflow with respect to the rearpart of the cove 5A.

FIG. 13 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 7 and the main wing when the slatis extended.

When the slat 3C is extended from the main wing 2, as shown in FIG. 13,part of the air flows from the leading edge 8 along the upper surface 9,and the rest thereof flows from the leading edge 8 along the lowersurface 10, in the same way as described above.

The air flowing along the lower surface 10 flows from the lower surface10 along the lower-surface plate 7A and is separated at the end of thelower-surface plate 7A. The separated air flows in the direction inwhich the lower-surface plate 7A extends, and then flows between thecove 5 of the slat main body 4 and the main wing 2 to collide againstthe inclined surface 12 of the inclined plate 6. The colliding air flowsalong the inclined surface 12 and the rear part, joins the air flowingalong the upper surface 9, and flows along the upper surface of the mainwing 2.

Compared with the above-described slat 3A of the conventional aspect,the airflow separated from the end of the lower-surface plate 7A flowsbetween the cove 5 and the main wing 2 to collide against the inclinedsurface 12 of the inclined plate 6. The inclined surface 12 has asmaller angle than the rear part of the cove 5A, with respect to theseparated air, thus reducing the collision angle of the airflow.

FIG. 14 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 8 and the main wing when the slatis extended.

When the slat 3 is extended from the main wing 2, as shown in FIG. 14,part of the air flows from the leading edge 8 along the upper surface 9,and the rest thereof flows from the leading edge 8 along the lowersurface 10, in the same way as described above.

The air flowing along the lower surface 10 flows from the lower surface10 along the lower-surface plate 7 and is separated at the end of thelower-surface plate 7. The separated air flows in the direction in whichthe lower-surface plate 7 extends, and then flows between the cove 5 ofthe slat main body 4 and the main wing 2 to collide against the inclinedsurface 12 of the inclined plate 6. The colliding air flows along theinclined surface 12, joins the air flowing along the upper surface 9,and flows along the upper surface of the main wing 2.

Compared with the slats 3A and 3C described above, the shear layer ofthe separated air is weakened due to the effect of the lower-surfaceplate 7 and the collision angle of the airflow with respect to theinclined surface 12 of the inclined plate 6 is reduced.

Compared with the above-described slat 3B, which has the samelower-surface plate 7, the collision angle of the airflow with respectto the inclined surface 12 of the inclined plate 6 is reduced due to theeffect of the inclined plate 6.

As described above, compared with the slats 3A, 3B, and 3C, the shearlayer of the separated air is weakened and the collision angle of theairflow is reduced. Therefore, it is considered that generation ofpressure fluctuation is suppressed to reduce the aerodynamic noise.

FIG. 15 is a view showing streamlines for explaining a flow fieldproduced around the slat shown in FIG. 9 and the main wing when the slatis extended.

Finally, when the slat 3D is extended from the main wing 2, as shown inFIG. 15, part of the air flows from the leading edge 8 along the uppersurface 9, and the rest thereof flows from the leading edge 8 along thelower surface 10, in the same way as described above.

The air flowing along the lower surface 10 flows from the lower surface10 along the curved surface 18 and flows between the slat main body 4and the main wing 2. Then, the airflow smoothly changes its directionalong the curved surface 18, joins the air flowing along the uppersurface 9, and flows along the upper surface of the main wing 2.

Since the air flows without collision, unlike the above-described cases,it is considered that the sound pressure level of generated aerodynamicnoise is the lowest among the above-described slats.

According to the above-described structure, when the slat main body 4 isextended from the main wing 2, part of the air flows along the lowersurface 10 of the slat main body 4 and is separated from the lowersurface 10. The separated air (shear layer) flows between the slat mainbody 4 and the main wing 2, collides against the inclined surface 12,and flows along the inclined surface 12 and the surface of the cove 5.

Since the angle of the inclined surface 12 of the inclined plate 6 withrespect to the central axis CL can be deflected, the collision angle ofthe above-mentioned shear layer and the inclined surface 12 can bedeflected. Therefore, compared with a case where a collision anglecannot be deflected, it is possible to suppress the occurrence ofaerodynamic noise by selecting a collision angle at which lessaerodynamic noise occurs.

On the other hand, compared with the technology described in U.S. Pat.No. 6,394,396, a smaller number of components is required, preventing anincrease in weight.

When the slat main body 4 is retracted into the main wing 2, the cove 5accommodates the leading edge of the main wing 2. At this time, sincethe angle of the inclined surface 12 with respect to the central axis CLcan be deflected, the angle of the inclined surface 12 is deflected atan angle for avoiding interference with the upper surface of the mainwing 2. Thus, the leading edge of the main wing 2 can be formed in ashape that does not impair the aerodynamic characteristics, withoutconsidering interference with the inclined surface 12 of the inclinedplate 6.

When the slat main body 4 is retracted into the main wing 2, the otherend of the inclined plate 6 pivots toward a location where interferencewith the leading edge of the main wing 2 does not occur and theaerodynamic characteristics are not impaired, in other words, it pivotsupward about the one end. Therefore, it is possible to avoidinterference by widening the gap between the inclined surface 12 and theupper surface of the main wing 2.

When the slat main body 4 is extended from the main wing 2, the end ofthe inclined plate 6 pivots downward with respect to the central axisCL, in other words, it pivots downward about the pivotal end 11.Therefore, the above-described collision angle of the airflow and theinclined surface 12 can be reduced.

When the slat main body 4 is retracted into the main wing 2, the cove 5accommodates the leading edge of the main wing 2. At this time, sincethe angle of the lower-surface plate 7 with respect to the central axiscan be deflected, the angle of the lower-surface plate 7 with respect tothe central axis CL is deflected at an angle for smoothly connecting thelower surface 10 of the slat main body 4 to the lower surface of themain wing 2. Thus, deterioration in the aerodynamic characteristics ofthe wing 1, having the slat main body 4 and the main wing 2, can berestricted.

When the slat main body 4 is extended from the main wing 2, part of theair flows along the lower surface 10 of the slat main body 4 and thelower-surface plate 7 and is separated from the lower-surface plate 7.Since the angle of the lower-surface plate 7 with respect to the centralaxis CL can be deflected, the direction of the separated air can bedeflected. Thus, compared with a case where the airflow is separatedfrom the lower-surface plate positioned in the same state as when theslat main body is retracted into the main wing, the direction of theseparated air can be deflected to weaken the shear layer, therebysuppressing the occurrence of aerodynamic noise.

On the other hand, the separated air flows between the slat main body 4and the main wing 2, collides against the inclined surface 12, and flowsalong the inclined surface 12 and the surface of the cove 5.

Since the angle of the lower-surface plate 7 with respect to the centralaxis CL can be deflected, it is possible to deflect the direction of theseparated air to deflect the collision angle of the separated air withrespect to the inclined surface 12. Therefore, compared with a casewhere the direction of the separated air cannot be deflected, it ispossible to suppress the occurrence of aerodynamic noise by selecting acollision angle at which less aerodynamic noise occurs.

On the other hand, even when the end of the lower-surface plate 7 thatis close to the main wing 2 pivots downward with respect to the centralaxis CL, if a porous plate or the like is used for the lower-surfaceplate 7, the shear layer of the separated air is weakened, therebyallowing a reduction in aerodynamic noise.

When the slat main body 4 is retracted into the main wing 2, the end ofthe lower-surface plate 7 that is close to the main wing 2 pivots towarda location where interference with the leading edge of the main wing 2does not occur and the aerodynamic characteristics are not impaired, inother words, it pivots downward. Therefore, it is possible to avoidinterference between the lower-surface plate 7 and the leading edge ofthe main wing 2. Further, the lower-surface plate 7 can smoothly connectthe lower surface 10 of the slat main body 4 to the lower surface of themain wing 2.

When the slat main body 4 is extended from the main wing 2, the end ofthe lower-surface plate 7 that is close to the main wing 2 pivots upwardwith respect to the central axis CL, in other words, it pivots upward.Therefore, it is possible to deflect the direction of the separated airto reduce the collision angle of the separated air with respect to theinclined surface 12.

Second Embodiment

Next, a second embodiment of the present invention will be describedwith reference to FIGS. 16 to 20.

Although the basic structure of a wing of this embodiment is the same asthat of the first embodiment, the structure of a noise reductionstructure in a slat is different from that of the first embodiment.Therefore, in this embodiment, only the slat and the componentssurrounding it will be described with reference to FIGS. 16 to 20, and adescription of the main wing etc. will be omitted.

FIG. 16 is a cross-sectional view for explaining the structure of theslat according to this embodiment. FIG. 17 is a cross-sectional view forexplaining the structure of an airflow control part shown in FIG. 16.FIG. 18 is a cross-sectional view for explaining a structure formounting the airflow control part shown in FIG. 17 to the slat.

Note that the same reference symbols are given to the same components asthose of the first embodiment, and a description thereof will beomitted.

As shown in FIGS. 16 to 18, the slat 3 of a wing 101 includes the slatmain body 4, the cove 5, and an airflow control part (noise reductionstructure) 106.

The airflow control part 106 is a part against which an airflowseparated at the lower-surface plate 7 collides and that suppresses theaerodynamic noise.

The airflow control part 106 includes a base plate 111, a seal part 112,an inclined plate 113, and holding parts 114. The base plate 111, theseal part 112, and the inclined plate 113 are integrally formed by usingan elastic member, such as silicone rubber, chloroprene rubber, nitrilerubber, fluorosilicone rubber, or fluororubber.

Thus, compared with a case where the inclined plate 113 is made by usinga material different from that of the seal part 112, etc., it ispossible to integrally form the airflow control part 106 by using anidentical material, such as rubber, which allows the airflow controlpart 106 to be formed easily. Further, since the airflow control part106 is integrally formed, the inclined plate 113 is hardly separatedfrom the seal part 112, etc.

The base plate 111 is a plate-like member that extends along a wallsurface of the slat main body 4. As shown in FIG. 18, the base plate 111fixes the airflow control part 106 to the slat main body 4 together withthe holding parts 114. Further, the seal part 112 is disposed in thevicinity of a leading-edge end (the left end in FIGS. 17 and 18) of thebase plate 111, and an end of the inclined plate 113 is disposed in thevicinity of a trailing-edge end (the right end in FIGS. 17 and 18) ofthe base plate 111.

The seal part 112 is a member that has an approximately C-shaped crosssection and that extends in the longitudinal direction (the directionperpendicular to the plane of the paper of FIGS. 17 and 18) of the slatmain body 4. The seal part 112 exerts a sealing function when the slatmain body 4 is retracted, and it exerts a function of maintaining theinclination of the inclined plate 113 at a predetermined angle by usingthe elasticity of the seal part 112 when the slat main body 4 isextended.

In the seal part 112, a cutout part 121 is provided that opens towardthe trailing edge of the wing 101 and that extends in the longitudinaldirection of the slat main body 4. An end of the base plate 111 isdisposed at an end (the upper end in FIGS. 17 and 18) of the seal part112 that is close to the slat main body 4, and an end of the inclinedplate 113 is disposed at the other end (the lower end in FIGS. 17 and18) of the seal part 112 that is close to the main wing 2.

The inclined plate 113 is a plate-like member against which the airflowseparated at the lower-surface plate 7 collides.

Of the inclined plate 113, the end close to the trailing edge (at theright side in FIGS. 17 and 18) is disposed on the base plate 111, andthe other end close to the leading edge (at the left side in FIGS. 17and 18) is disposed on the seal part 112.

In other words, the end of the inclined plate 113 that is close to theleading edge is supported by the seal part 112 so as to be able toextend from and retract into the central axis CL (see FIG. 16). Theinclined plate 113 serves as an inclined surface that is inclined upwardwith respect to the main wing 2.

A sliding layer 131 that is made of polytetrafluoroethylene (Teflon(registered trademark)), polyester, or the like is provided on thesurface of the inclined plate 113 that faces the main wing 2. Morespecifically, the sliding layer 131 is provided in an area that contactsthe main wing 2 when the slat main body 4 is retracted.

The holding parts 114 are a pair of plate-like members that extend alongthe wall surface of the slat main body 4. As shown in FIG. 18, theholding parts 114 sandwich the base plate 111 between the holding parts114 and the slat main body 4 to fix the airflow control part 106 to theslat main body 4.

One of the holding parts 114 that is close to the leading edge isdisposed to sandwich the base plate 111, which extends toward theleading edge further than the seal part 112, between the holding part114 and the slat main body 4, and is fixed to the slat main body 4 withfasteners such as screws.

The other one of the holding parts 114 that is close to the trailingedge is disposed to sandwich the base plate 111, which extends towardthe trailing edge further than the inclined plate 113, between theholding part 114 and the slat main body 4, and is fixed to the slat mainbody 4 with fasteners such as screws.

Next, the operation of the wing 101, having the above-describedstructure, will be described.

FIG. 19 is a view for explaining the state of the airflow control partwhen the slat is extended from the main wing.

When aircraft provided with the wing 101 is about to land or take off,the slat 3 is extended, as shown in FIG. 19, in order to realize theaerodynamic characteristics required at the time of landing or takeoff.

At the same time, the seal part 112 that was elastically deformedrestores its original shape, and thus the end of the inclined plate 113that is close to the leading edge pivots downward.

FIG. 20 is a view for explaining the state of the airflow control partwhen the slat is retracted into the main wing.

When the aircraft provided with the wing 101 is in the cruising state,the slat 3 is retracted into the main wing 2, as shown in FIG. 20.

At this time, the seal part 112 and the inclined plate 113 of theairflow control part 106 are brought into contact with the main wing 2.The seal part 112 is pressed and deformed by the main wing 2 and theslat main body 4. On the other hand, the inclined plate 113 approachesthe slat main body 4. Therefore, interference between the airflowcontrol part 106 and the leading edge and upper surface of the main wing2 can be avoided.

Further, when the slat 3 is being extended or retracted, the slidinglayer 131 on the inclined plate 113 moves from the leading edge side tothe trailing edge side or from the trailing edge side to the leadingedge side, while being in contact with the main wing 2. Since thesliding layer 131 is made of a material that has a low frictioncoefficient, such as polytetrafluoroethylene, the frictional resistancegenerated when the inclined plate 113 and the main wing 2 relativelymove is reduced.

In other words, it is possible to restrict an increase in the loadimposed on an actuator (not shown) that extends and retracts the slat 3.

According to the above-described structure, when the slat main body 4 isretracted into the main wing 2, the seal part 112 is brought intocontact with the upper surface of the main wing 2. Therefore, a gapbetween the slat main body 4 and the main wing 2 is sealed, thuspreventing water, dust, etc. from entering the cove 5.

Further, since the seal part 112 is brought into contact with the uppersurface of the main wing 2 and deformed, the end of the inclined plate113 that is close to the leading edge is deformed toward a locationwhere interference with the leading edge of the main wing 2 does notoccur and the aerodynamic characteristics are not impaired. In otherwords, it is deformed upward about the end close to the trailing edge(that is, in the direction in which it moves away from the central axisCL (see FIG. 16)).

Therefore, the airflow control part 106 can be accommodated in the gapbetween the slat main body 4 and the upper surface of the main wing 2without interference.

On the other hand, when the slat main body 4 is extended from the mainwing 2, the shape of the seal part 112 that was in contact with andpressed by the upper surface of the main wing 2 is restored.Accordingly, the shape of the inclined plate 113 that was deformedupward with respect to the central axis CL (see FIG. 16) about the endclose to the trailing edge is also restored.

Therefore, the collision angle of the above-mentioned shear layer andthe inclined plate 113 can be reduced.

FIG. 21 is a cross-sectional view for explaining another embodiment ofthe airflow control part shown in FIG. 17. FIG. 22 is a cross-sectionalview for explaining a structure for mounting an airflow control partshown in FIG. 21 to the slat.

Note that the seal part 112 may be provided with the cutout part 121, asdescribed above, or the seal part 112 may not be provided with thecutout part 121, as shown in FIG. 21; the structure of the seal part 112is not particularly limited.

When the airflow control part 106 has the seal part 112 that is notprovided with the cutout part 121, the holding part 114 may be disposedbetween the inclined plate 113 and the slat main body 4 to mount theairflow control part 106 to the slat main body 4, as shown in FIG. 22;the location of the holding part 114 is not particularly limited.

In other words, the holding part 114 may be disposed so as to sandwichthe base plate 111 that extends from the seal part 112 toward thetrailing edge, between the holding part 114 and the slat main body 4.

FIG. 23 is a cross-sectional view for explaining still anotherembodiment of the airflow control part shown in FIG. 17.

Note that, as described above, the inclined plate 113 may be made ofrubber, which is an elastic member, like the seal part 112, or, as shownin FIG. 23, an inclined plate 113A may be made of a rigid material, suchas a synthetic resin or metal, unlike the seal part 112 etc.; thematerial used for the inclined plate is not particularly limited.

Thus, compared with the inclined plate 113 made of rubber or the like,even when an airflow collides against the inclined plate 113A, theinclined plate 113A is less deformed, thus more effectively suppressingthe turbulence of the colliding airflow. In short, it is possible tosuppress the occurrence of aerodynamic noise caused by turbulence.

Third Embodiment

Next, a third embodiment of the present invention will be described withreference to FIG. 24.

Although the basic structure of a wing of this embodiment is the same asthat of the second embodiment, the structure of a noise reduction isdifferent from that of the second embodiment. Therefore, in thisembodiment, only the slat and the components surrounding it will bedescribed with reference to FIG. 24, and a description of the main wingetc. will be omitted.

FIG. 24 is a cross-sectional view for explaining the structure of anairflow control part according to this embodiment.

Note that the same reference symbols are given to the same components asthose of the second embodiment, and a description thereof will beomitted.

As shown in FIG. 24, the slat 3 of a wing 201 includes the slat mainbody 4, the cove 5, and an airflow control part (noise reductionstructure) 206.

The airflow control part 206 suppresses the turbulence.

The airflow control part 206 includes the base plate 111, the seal part112, and a shock absorbing part 213. The base plate 111 and the sealpart 112 are integrally formed by using an elastic member, such assilicone rubber, chloroprene rubber, nitrile rubber, fluorosiliconerubber, or fluororubber.

The shock absorbing part 213 is a part against which an airflowseparated at the lower-surface plate 7 collides and that suppresses theturbulence.

The shock absorbing part 213 has a flocculent material formed of aplurality of fibers, for example, polyester fibers, that extend towardthe main wing 2 from the base plate 111, which extends from the sealpart 112 toward the trailing edge. In other words, the shock absorbingpart 213 has a flocculent material formed of thin soft fibers, like birdfeathers and down, or a flocculent material obtained by mixingthreadlike synthetic fibers into the thin soft fibers like feathers anddown and by making them fire retardant.

In other words still, the plurality of fibers constituting theflocculent material are planted in the base plate 111, like mouton or aboa.

On the other hand, an end surface of the shock absorbing part 213 thatis close to the main wing 2 is formed as an inclined surface thatapproaches the base plate 111 from the leading edge side to the trailingedge side.

Next, the operation of the wing 201, having the above-describedstructure, will be described.

When aircraft provided with the wing 201 is about to land or take off,the slat 3 is extended in order to realize the aerodynamiccharacteristics required at the time of landing or takeoff.

At the same time, the seal part 112 that was elastically deformedrestores its original shape.

On the other hand, an airflow separated from the lower surface of theslat main body 4 collides against the shock absorbing part 213, and theenergy of the airflow is absorbed by the shock absorbing part 213.

When the aircraft provided with the wing 201 is in the cruising state,the slat 3 is retracted into the main wing 2.

At this time, the seal part 112 and the shock absorbing part 213 of theairflow control part 206 are brought into contact with the main wing 2.The seal part 112 is pressed and deformed by the main wing 2 and theslat main body 4. On the other hand, the shock absorbing part 213 isalso pressed and deformed by the main wing 2. Therefore, interferencebetween the airflow control part 206 and the leading edge and uppersurface of the main wing 2 can be avoided.

According to the above-described structure, when the slat main body 4 isextended from the main wing 2, an air (shear layer) separated from thelower surface of the slat main body 4 flows between the slat main body 4and the main wing 2, collides against the shock absorbing part 213, andflows along the shock absorbing part 213 and the surface of the cove 5.

When the separated air collides against the shock absorbing part 213,the shock absorbing part 213 absorbs part of the energy of the airflow.Therefore, it is possible to reduce the aerodynamic noise generated bythe airflow after it collides against the shock absorbing part 213.

The invention claimed is:
 1. A high-lift device comprising: a slat mainbody that is disposed so as to be able to extend from and retract into amain wing; a concave part that is formed on the slat main body at alocation that faces the main wing, so as to be able to accommodate atleast a part of a leading edge of the main wing; and a lower-surfaceplate that is a plate member extending along an extended line of a lowersurface of the slat main body toward the main wing from an edge line atwhich the lower surface of the slat main body and the concave part meetwhen the slat main body is extended from the main wing, wherein thelower-surface plate is configured to be able to deflect an angle thereofwith respect to a central axis of the slat main body, at a trailing edgeof the lower-surface plate, saw-shaped serrations are provided along alongitudinal direction of the lower-surface plate, and when the angle oflower-surface plate is deflected upwardly with respect to the centralaxis of the slat main body, the lower-surface plate deflects a directionof a separated air upwardly, and the serrations weaken a shear layer ofthe separated air.
 2. A high-lift device according to claim 1, wherein:the lower-surface plate is pivotably supported at the edge line on theslat main body; and a trailing end of the lower-surface plate ispositioned at a location where interference with the leading edge of themain wing does not occur and aerodynamic characteristics are notimpaired, in a state where the slat main body is refracted into the mainwing, and moves upward or downward with respect to the central axis ofthe slat main body when the slat main body is extended from the mainwing.
 3. A high-lift device according to claim 1, wherein thelower-surface plate is made of a member through which air does not pass,a member through which a part of the air passes, or a combinationthereof.
 4. A wing comprising: a main wing; and a high-lift deviceaccording to claim 1 that is disposed so as to be able to extend fromand retract into a leading edge of the main wing.
 5. A high-lift deviceaccording to claim 1, further comprising: an airflow control part thatis disposed at an area in the concave part facing an upper surface ofthe main wing, the airflow control part being accommodated between themain wing and the concave part when the slat main body is retracted intothe main wing, and the airflow control part suppressing turbulencecolliding against the area in the concave part facing the upper surfaceof the main wing when the slat main body is extended from the main wing.6. A high-lift device according to claim 5, wherein the airflow controlpart is a plate member extending from the concave part.
 7. A high-liftdevice according to claim 6, wherein the airflow control part has afirst end that is attached to the concave part at a downstream positionand a second end that is free from attachment to the concave part at anupstream position.
 8. A high-lift device according to claim 7, whereinthe first end of the airflow control part is pivotably attached to theconcave part.
 9. A high-lift device according to claim 8, wherein theairflow control part includes an elastic member that biases the airflowcontrol part towards the main wing when the slat main body is extendedfrom the main wing.
 10. A high-lift device according to claim 7, whereina distance between a surface of the airflow control part facing theconcave part increases in a direction from the first end at thedownstream position to the second end at the upstream position when theslat main body is extended from the main wing.
 11. A high-lift deviceaccording to claim 5, wherein the airflow control part includes: a baseplate fixed to the concave part; a seal part; and an inclined plate,wherein the base plate, the seal part and the inclined plate areintegrally formed as an elastic member and have a cutout parttherebetween, wherein the seal part is located at an upstream positionbetween the base plate and the inclined plate, and the base plate andthe inclined plate meet at a downstream position, and wherein the sealpart biases an upstream end of the inclined plate away from an upstreamend of the base plate when the slat main body is extended from the mainwing.
 12. A high-lift device according to claim 11, wherein the sealpart has a C-shaped cross-section and extends in the longitudinaldirection of the lower-surface plate.